Various types of convertible cot and patient transport assemblies are known in the prior art. A first example of such a device is disclosed in the multiple purpose ambulance cot with removable stretcher top set forth in U.S. Pat. No. 4,037,871, to Bourgraf. The ambulance cot includes a base structure which serves as a carrier for a removable stretcher forming a top for the carrier.
Loescher, U.S. Pat. No. 5,345,881, teaches a folding table mechanism employing hollow rail members which support the mechanism therebetween. A pair of legs are mounted to the ends of a stretcher member to form a folding unit, and which is both translated and rotationally connected to the rail members by an over center cam mechanism operated by a lock bar capable of exerting locking force in both the unfolded and folded positions of the table legs.
Wicks, U.S. Pat. No. 3,167,789, teaches a patient supporting and carrying means for operating as a stretcher table and hospital bed and which includes multiple hinged and assembleable sections. Bono, U.S. Pat. No. 5,201,536, discloses a multi-purpose combination carrier cart/table.